Valve guide scraper ring



Oct. 17, 1944. L F HUDDLESTON 2,360,606

VALVE GUIDE SCRAPER RING Filed May 8, 1945 I NVEN TOR.

Patented Oct. 17, 1944 -U NlTE -D STATES" PATENT OFFICE VALVE GUIDE-SCRAPER RING i 1 l g 1 Robert F. Huddleston, IndianapoliaInd; assign r lor to P. R. Mallory .& 06., Inc.,I n'dian'apolis,

Indqa corporation of Delaware' Application May 8, 19.43, serial No.486,179

4 Claims. (01.123-188)" v This inventioul elatesto engine valve guides.An object of the invention is to improve valve guides and valve guidescraper. rings and their method ,of mounting.

Other objects of the invention will be apparent from the descriptionandclaims.

In'the drawin Iv Figure 1 is a section through-a valve assemblyillustrating the, mounting of a valve'guide and Figure 2 is a section onthe line 2-2 of Figure 1;

enters the valve guide. or guide made of other commonly used metals,

"however; is not ofsufficient hardness and abrasion resistance to scrapeoff the carbon over extended periods of operation. According to thepresent invention the valve guide is provided with a scraper ring ofhard refractory metal composition, the scraper ring being secured to thevalve guide by interlocking portions.

Refering to the drawing the valve assembly shown in Figure 1 comprises avalve seated in a valve seat I I in the engine block l2. Valve ID has astem portion l3 which slides in a valve guide [4 secured in the engineblock or cylinder head. Guide I4 carries at its end nearest the head ofthe valve the scraper ring I5 formed of a hard refractory metalcomposition.

The valve guide I4 is illustrated in Figure 4 and the scraper ring IS inFigure 3.

Valve guide scraper ring I 5 is produced by powder metallurgy methods ofmixtures of refractory metal powders with bonding metals. The preferredcomposition and method of manufacture is as follows: The finalcomposition ranges from 55% to 65% molybdenum, 45% to 35% silver. Smallpercentages of copper, cobalt, nickel, iron, manganese, and carbon maybe present. While several methods may be used in the manufacture ofvalve guide scraper rings, I prefer to mix molybdenum powder witha.small percentage of silver powder, press, sihter at,a sufii- Figure 3 1sa perspective view of a 'valveguide scraper ring; and I v Figure 4 is aperspective view ofthe valve guide -for holding the scraper ring., 1 'Intheoperation of internal combustion en- 'gines such as airplane enginesunder some conditions carbon deposits are built up on the valve 'stem'sca'tsing rapid wear and damage to the 'valve guides and valve stem. Itis desirable "therefore to provide a means for removing the carbonfrom'the portion of the valve stem which An ordinary steel guideofmanufacture. l0

cientlyhigh temperature tocause bonding, of the f refractory molybdenumV particles. and .subsequently impregnate with additional silver at atemperature above the melting point of silver so as to form a strong,homogeneous, denseproduct having high physical. properties coup.led.with good electrical and thermal conductivity. I do not wish, however,to be limited to this method Other methods which. have proven successfulhave been:

-a. Mix all of the .powders sinter. at a temperature below. themeltingpoint of either the molybdenum or silver. 1

, b. Mix all of the powders together, press and s inter at a temperatureabove the melting point of silver but below the melting-point ofmolybdenum.

0. Press molybdenum powder to a suitable density, sinter at asufiiciently high. temperature to cause-bonding of themolybdenumpparticles and incorporate all of the silver by. impregnatingat a temperature above the melting point of silver.

Other refractory metal compositions which can be used are: 7

50% to 80% tungsten, balan'ce silver 40% to 70% tungsten carbide,balance silver 30% to 70% molybdenum carbide, balance silver 25% to 50%titanium carbide, balance silver 40% to 70% tantalum carbide, balancesilver. 1

Small percentages of copper, cobalt, nickel, iron or manganese may alsobe present. Various percentages of the refractory elements or carbidesmay bermixed with each other.

These compositions may be prepared in a manner similar to that used tofabricate the preferred composition.

The scraper ring is preferably molded in a die to substantially thefinal shape and dimensions required and then a finish machiningoperation is applied after sintering and alloying. As illustrated inFigures 1 and 3 the scraper ring has a central cylindrical opening l6passing therethrough. The scraping face I! is formed on the largerdiameter end 2| of the ring with a conical surface to give asatisfactory cutting edge and carry carbon particles away from the valvestem. The smaller endi of the scraper ring is provided with a conicaltapered portion 18 to aid in assembly, this tapered portion merging withan annular ridge IS, a short distance back from the smaller end of thering. An annular groove 20 is protogether, press and to rotate withinthe guide.

Valve guide I. is formed of a tubular piece-of -metal and is adapted toreceive scraper ring l by machining a pair of annular grooves '22 and d3 on its inside surface near one end. The groove :iortion is alsoslotted with SIX equally spaced longitudinal slots 24 to divide the endof the guide into six legs 26. .The other lender the guide is .providedwith an enlarged portion 25.

:The parts are assembled by inserting the tapered smaller end ll! of thescraper ring in the The scraper ring at this time is free Annular groove23 in=.the guide member permits sufficient flexibility the guide.

.of the six legs to permit assembly as above described.

;The valve guide and; scraper ring-assembly is .then inserted in theaperture in the engine block *or. cylinder head provided for it.'This'aperture ,tightly. engages the outer surfaceof valve'guide =14firmly pressing the six legs 26 against the scraper ring to prevent anyrelative motion after final assembly.

By this method of assemby no welding or brazing; is required between thevalve guide and the scraper ring. Moreover it is frequently necessary ordesirable to replace the scraper rings during service. I operation verysimple, it merely being necessary The present invention makes thistowithdraw the valve guide, remove the'worn scraper ring and snap in anewring.

-While specific embodiments of the invention have been described, it isintended to coverthe invention broadly within the spirit and scope ofthe appended claims. What is claimed is:

1. A valve guide assembly comprising a tubular I metal guide havinganinternal annulargroove tudinal slots extending 'ing of said legs.

= grooved portion into near one of its endsand a plurality of longibackfrom said end to divide the grooved portion into a plurality ofindividual resilient legs, and a scraper ring having an external:annular flange received in said internal annular groovewhereby saidguide and ring are locked together.

2. A'valve guide assembly comprising a tubular .metal guide having aninternal annular groove near one of its ends and a plurality oflongitudinal slots extending back from said end to divide the groovedportion into a plurality of individual resilient legs, and a scraperring having an external annular flange received in said internal annulargroove whereby said guide-and ring are locked together, one of saidparts having a tapered conical face at its end to produce spread- 3. Avalve guide assembly comprising a tubular metal guide having-an internalannular groove near one of its ends separated from said end by aninternal flange and a plurality of longitudinal slots extending backfrom said end to divide the .a plurality of individual groove whereby:said guide and ring are lockedtogether.

4. A valve guide assembly comprisingatubular metal guide having.aninternal annular groove near one of. its"endsseparated' from-said endby an internal flange and a pluralityof longitudinal slots extendingback frornsaid end to-divide the a pluralityof individual resilientlegs,- and a scraper ring of hardrefractory metal having anexternalflange received in said internal annular groove whereby saidguide and ring'are locked together,-said-scraper ring-having a conicalsurface flaring outward from oneof its ends and merging withsaidexternal flange to produce spreading ofv said guide'legsduringassembly,

- ROBERT F. HUDDLESTON.

